In view of the increasing costs of energy a demand has arisen for lighting sources which use less power. In many areas, simply replacing incandescent light sources with fluorescent tubes can accomplish this result. However, in those places already employing fluorescent tubes, there still remains a need to reduce energy consumption. This can sometimes be accomplished by removing some of the overhead lamps or by removing one lamp of a series pair and replacing it with a dummy lamp containing a capacitor. Such techniques usually affect the lighting distribution.
Another method which has been employed involves detaching some of the wires between a fluorescent lamp ballast and the lamp, and then connecting in the circuit a transformer-capacitor combination, as disclosed in U.S. Pat. No. 3,954,316. This technique, of course, involves rewiring.
Still another approach, used with elongated fluorescent tubes, is to employ a lamp which is shorter than the distance between the socket in which the lamp is mounted. This distance is made up by attaching to one end of the lamp an extension base which contains power reducing circuitry. Such a device is shown in U.S. Pat. No. 4,163,176 and has enjoyed much success; however, the dark space at the end of the lamp is noticeable and occasionally objectionable. Also, the pressure of the starting gas in the shorter tube is increased over that of the standard bulb it replaces.
Further, there has been no reasonable way to apply these energy saving ideas to other configurations of fluorescent lamps.